Exercise intolerance is a major symptom in patients (pts) with congestive heart failure (CHF). A lack of correlation between the left ventricular systolic dysfunction and exercise capacity was found. Recently, it has been proposed that diastolic dysfunction may contribute to significant impairment of exercise tolerance in pts with CHF. The aim of the study was to compare the relationship between Doppler indices of diastolic function and exercise capacity in patients with CHF.
Material and methods: The study included 29 pts (20 M, 9 F) 14 with idiopathic and 15 with ischaemic cardiomyopathy. The mean left ventricular ejection fraction (LVEF) was 31 +/- 8%, VO2peak was 16.4 +/- 4.6 ml/kg/min. The mean age was 55.4 +/- 12.1, ranged from 30 to 73 years. All pts underwent complete echocardiography study. Diastolic performance was estimated using conventional Doppler mitral inflow (E, A) velocities, E/A ratio, deceleration time of E velocity (E-DT), isovolumetric relaxation time (IVRT) and color Doppler M-mode flow propagation velocity (Vp). Resting spirometry and cardiopulmonary exercise test (CPX) were performed in all pts. Exercise capacity was measured as oxygen consumption at peak exercise (VO2peak). The association between echocardiography parameters and VO2peak was evaluated by Spearman's correlation coefficients (r).
Results: We found that VO2peak correlated significantly with the LV filling pattern estimated by the transmitral Doppler E/A ratio (r=-0.4, p=0.03), A-wave velocity (r=0.4, p=0.03) and velocity flow propagation (r=0.4, p=0.05). There was no correlation between VO2peak and following mitral inflow parameters: (E-wave, DT, IVRT). There was no correlation between VO2peak and LVEF.
Conclusions: 1. Doppler indices of diastolic function are important determinants of exercise capacity in CHF pts. 2. Assessment of transmitral flow velocities holds a substantial diagnostic potential, which may be utilized in everyday clinical practice as a alternative in routine monitoring of systolic heart failure.